A significant body of scientific and clinical evidence supports atherectomy as a viable primary or adjunctive therapy prior to stenting for the treatment of occlusive arterial disease. Atherectomy offers a simple mechanical advantage over alternative therapies. By removing the majority of plaque mass (debulking), a larger initial lumen is created. As a result, stent deployment is greatly enhanced. Moreover, there are advantages to atherectomy related to the arterial healing response. When circumferential radial forces are applied to the vasculature, as in the case of angioplasty or stenting, the plaque mass is displaced, forcing the vessel wall to stretch dramatically. This stretch induces injury which is a known stimulus for the cellular in-growth that leads to restenosis. By removing the disease with minimal force applied to the vessel and reducing the plaque burden prior to stent placement, large gains in lumen size can be created with decreased vessel wall injury and limited elastic recoiling. These effects have been shown to generate better acute results and lower restenosis rates.
Traditional atherectomy devices have been plagued by a number of problems that have severely limited market adoption of these devices. A significant concern in adopting these devices is that they tend to require the use of large, cumbersome, and expensive drive assemblies to control the rotation and/or axial translation of the atherectomy cutter. The drive assemblies described herein may overcome some of these hurdles.